Janet is 5 years older than her sister. the sum of their ages is 51. how old is her sister

To find how old old her sister is you just do 51 - 5 which will give you 46.

Let us assume that the age of Janet's sister is = x

Then the age of Janet = x + 5

Now we also know that their combined age is equal to 51 years. Then we can write the equation as

x + (x + 5) = 51

2x + 5 = 51

2x = 51 - 5

2x = 46

x = 46/2

= 23

So the age of Janet = x + 5

= 23 + 5

= 28 years

So the age of Janet's sister is 23 and Janet's age is 28